Drilling a hole in shaft after new prop install

[Stefanojo]

So I got myself a new Campbell Sailor prop (love it).  The diver I hired to install it has been trying to drill a hole through the shaft in order to put a pin through it to secure the second nut. He told me this is SOP. The problem is is he hasn't been able to drill a hole through the shaft. He's broken multiple bits and supposedly has the correct gear. He's been in consultation with our local prop shop. It just seems odd. He thinks the shaft is made out of something other than stainless. I have no idea. Figured I'd check in with the brain trust

[waughoo]

Stainless can be pretty problematic to drill.  I can only imaging the added challenges of doing it under water. 

[Noah]

I hate to be a naysayer but...wasn't there a hole already drilled in your shaft for your previous prop? How do you lap fit the taper of the shaft/prop while in the water? Perhaps you should abandon this underwater effort and  do a "short haul" at a boatyard-—taking care of those issues while hanging in the slings?

[Ron Hill]

Steve : I agree with Noah, you already have a hole thru the shaft for a cotter pin that secured your old prop. Can't you use it for a new cotter pin thru the new prop???

A thought

[KWKloeber]

I he has the correct gear, he will be using a cobalt drill bit on stainless steel.

[Robert Mann]

When I installed my Campbell Sailor I had a similar issue.  When the PO installed a folding prop they butchered the stainless shaft, when fitting the prop, and cut off the portion of the thread with the cotter pin hole.  Fortunately I was on the` hard when I did this swap.  I used a Milwaukee cobalt drill bit and copious quantities of cutting oil.  If you get the speed correct and the pressure on the drill just right it will drill quite well, even producing nice curly cuttings!  Now doing that under water, I think, would be extremely difficult.  A phosphor bronze shaft maybe, stainless could be a different story.

[KWKloeber]

Except for getting it started correctly the rest won't be that bad if it's a good mechanic.

Cutting oil is a misnomer and is not for "cutting" but to cool the work (high sulfur content cooling fluid) and not to lubricate it.  Think of it, the goal is not to introduce slippage between the cutting edge and work, which would be counter productive. 

So in water, heat becomes a non-issue. 
In fact, one of my clients has converted half their screw cutting machines from oil based  cooling fluid to water based!